1. Field of the Invention
The present invention relates to a temperature setting method of a thermal processing plate, a computer-readable recording medium recording a program thereon, and a temperature setting apparatus for a thermal processing plate.
2. Description of the Related Art
In a photolithography process in manufacturing, for example, a semiconductor device, for example, a resist coating treatment of applying a resist solution onto a wafer to form a resist film, exposure processing of exposing the resist film into a predetermined pattern, heating processing of accelerating the chemical reaction in the resist film after exposure (post-exposure baking), and developing treatment of developing the exposed resist film are performed in sequence, so that the series of wafer processing forms a predetermined resist pattern on the wafer.
For example, the heating processing such as the above-described post-exposure baking is usually performed in a heating processing apparatus. The heating processing apparatus includes a thermal plate for mounting and heating the wafer thereon. The thermal plate has a heater embedded therein which generates heat by power feeding, and the heat generated by the heater adjusts the thermal plate to a predetermined temperature.
The thermal processing temperature in the above-described heating processing greatly affects the line width of the resist pattern to be finally formed on the wafer. Hence, to strictly control the temperature within the wafer during heating, the thermal plate of the above-described heating processing apparatus is divided into a plurality of regions, and an independent heater is embedded in each of the regions to adjust the temperature for each of the regions.
It is known that if the temperature adjustment for all of the regions of the above-described thermal plate is performed at the same set temperature, the temperature may vary within the wafer on the thermal plate, for example, due to the difference in thermal resistance between the regions, resulting in variations in the line width of the resist pattern. For this reason, a temperature correction value (a temperature offset value) is further set for each of the regions of the thermal plate to finely adjust the in-plane temperature of the thermal plate (see Japanese Patent Application Laid-open No. 2001-143850).
For setting the above-described temperature correction value, the current line widths within the wafer are first measured, and an operator sets appropriate temperature correction values according to empirical rule based on measurement values. Thereafter, the line widths within the wafer are measure again, and the operator changes the temperature correction values in consideration of the line width measurement results. After operations of the line width measurement and the change of the temperature correction values are repeated through a try and error process, the setting of the temperature correction values comes to ends at a point in time when the operator judges that the line widths have reached an appropriate line width.
However, since the temperature correction values are determined after each of the temperature correction values is changed many times through a try and error process in the above-described temperature setting, it takes a very long time to complete the operation of temperature setting. Further, it is difficult to judge whether or not the temperature correction values at a point in time are optimal values to provide the best line widths halfway through the temperature setting operation, and therefore it is necessary to end the temperature setting operation at the point in time when the operator presumes that the line widths are appropriate by his/her subjectivity. As a result, an appropriate temperature setting may not have been made, thus causing large variations in line width within the wafer.